The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A fuel system delivers fuel to a direct injection engine at an injection pressure. For example, the injection pressure may include a range of 5-12 Megapascals (MPa). The fuel system may include a fuel tank, a low-pressure pump, a high-pressure pump, a fuel rail, and fuel injectors. The low-pressure pump delivers fuel from the fuel tank to the high-pressure pump. A camshaft may drive the high-pressure pump to pressurize fuel to the injection pressure. The high-pressure pump delivers fuel at the injection pressure to the fuel injectors via the fuel rail. The high-pressure pump may include a fuel supply control valve (hereinafter “control valve”). The control valve regulates an amount of fuel flowing from the low-pressure pump into the high-pressure pump. An engine control module actuates the control valve to regulate the injection pressure in the fuel rail. The engine control module may actuate the control valve based on a position of the camshaft relative to a position of a crankshaft.